Squamous vs. Non-Squamous NSCLC: What's the Difference
Squamous cell carcinoma and non-squamous NSCLC (primarily adenocarcinoma) are the two broad NSCLC categories, distinguished by how the cancer cells appear under a microscope, with different typical treatment approaches and biomarker patterns.
Squamous cell carcinoma begins in the flat cells lining the airways and has historically been more strongly associated with smoking history than adenocarcinoma. Adenocarcinoma, the most common non-squamous subtype, begins in mucus-producing cells and occurs more frequently in never-smokers.
Actionable driver mutations such as EGFR, ALK, and ROS1 are considerably more common in non-squamous NSCLC (particularly adenocarcinoma) than in squamous cell carcinoma, which has historically meant fewer targeted therapy options for squamous patients and a heavier reliance on immunotherapy and chemotherapy combinations.
Recent trial data, including the phase 3 HARMONi-6 study testing a dual PD-1/VEGF-targeting antibody, has specifically focused on improving outcomes for squamous NSCLC patients without a targetable driver mutation โ a population that has had comparatively fewer treatment advances than biomarker-positive non-squamous NSCLC in recent years.
Frequently Asked Questions
Which is more common, squamous or non-squamous NSCLC?
Adenocarcinoma (non-squamous) has become the most common NSCLC subtype in many countries over recent decades.
Do squamous and non-squamous NSCLC get treated the same way?
Not always โ treatment planning considers subtype alongside biomarker testing results, since targetable mutations occur at different rates between the two categories.